P0991: Transmission Fluid Pressure Sensor/Switch E Circuit Intermittent
What to do
One odd gear change in an otherwise normal journey. Note whether it happens once the car is thoroughly warm.
What this code means
The fifth pressure signal drops out or jumps briefly, producing an occasional bad pressure correction and the single unexplained hard or slipping shift that follows. The internal harness and its pass-through connector are the usual causes.
Likely causes
Start here
- Damaged transmission wiring harness · moderate
- Fluid tracking into the transmission connector · moderate
- Corroded transmission connector · moderate
Less common
- Faulty transmission fluid pressure sensor · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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